Dosing system for a concentrated laundry composition

ABSTRACT

A laundry detergent system comprising a highly concentrated liquid laundry detergent and a device connected to a water supply feed, that provides the injection pressure of the detergent composition being greater than water flow pressure at the junction of the detergent composition and the water flow and water flow rate at the junction of greater than 0.25 m/sec; wherein the flow rate ratio of the detergent composition to the water flow is in the range of from about 0.0001 to about 0.5.

FIELD OF THE INVENTION

Laundry detergent system for dispensing a concentrated laundry detergentcomposition into an automatic laundry washing machine, and methods foruse thereof.

BACKGROUND OF THE INVENTION

Highly concentrated liquid detergent compositions (HCLD), withsurfactant concentration range between 50% to 100%, are not readilyavailable in the consumer market due to their difficulty in dispensing,and/or dispersion and/or dissolution in the wash. One of the majorproblems is the HCLD's tendency to gel upon contact with water. HCLDs,however, are advantageous in many ways. One advantage is lowering thepackaging cost. Another benefit is the decrease in shipping cost due tothe reduction of non-functional components such as water. Also,stability of such compositions is improved—the minimal amount of waterin the detergent composition does not provide ground for growth ofmicroorganisms, thus reducing or even eliminating the use ofpreservatives. Also, due to the low amount of water, stability ofwater-sensitive ingredients, such as enzymes, is improved, removing theneed for non-functional stabilizers.

Various devices for delivering ingredients in a controllable way towashing machines have been described. See, for instance U.S. Pat. No.4,981,024, U.S. Pat. No. 3,982,666, U.S. Pat. No. 3,881,328, U.S. Pat.No. 4,103,520, U.S. Pat. No. 4,932,227, EP 0611,159, U.S. Pat. No.5,207,080, US 2003/0116177, U.S. Pat. No. 4,103,520, EP 1088927, WO03/033804, US 2004/088796, WO 03/069043, US 2003/0182732, and GB 2 134078.

If a method or device can be developed in preventing the gelling of theHCLD and helping the dispersion and dissolution of such compositions inthe wash, then consumers can receive a range of benefits including asmaller and lighter detergent package, and lower costs withoutcompromising the quality of the product.

The present invention is based at least in part on the discovery that bydispensing HCLD with a fast-moving or high shear water flow, thephenomenon of HCLD forming a gel in water, which contributed to thedifficulty of dispersion and dissolution in water, is eliminated. Bycombining HLCD with the appropriate dispensing method, HCLD use by theconsumers can be rendered commercially feasible.

SUMMARY OF THE INVENTION

The present invention includes, in its first embodiment, a laundrydetergent system comprising:

-   (a) a highly concentrated liquid laundry detergent composition    comprising:-   (a1) a surfactant, selected from anionic, nonionic, cationic    surfactants and mixtures thereof in an amount of from about 50% to    about 100%, by weight of the composition; and-   (a2) a solvent in an amount of from about 0% to about 10%; and-   (b) a device connected to a water supply feed, that provides the    injection pressure of the detergent composition being greater than    water flow pressure at the junction of the detergent composition and    the water flow and water flow rate at the junction of greater than    0.25 m/sec;-   (c) wherein the flow rate ratio of the detergent composition to the    water flow is in the range of from about 0.0001 to about 0.5.

The inventive system is suitable for residential washing machines, aswell as industrial, or commercial washing machines. The inventive deviceis suitable for use with front-loading or top-loading washing machines.

The following detailed description and the drawings illustrate some ofthe effects of the inventive compositions. The invention and the claims,however, are not limited to the following description and drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic drawing of the preferred embodiment of theinvention, employing a reducer.

DETAILED DESCRIPTION OF THE INVENTION

Except in the operating and comparative examples, or where otherwiseexplicitly indicated, all numbers in this description indicating amountsof material or conditions of reaction, physical properties of materialsand/or use are to be understood as modified by the word “about.”

It should be noted that in specifying any range of time or physicalconditions, any particular upper limit can be associated with anyparticular lower limit.

For the avoidance of doubt the word “comprising” is intended to mean“including” but not necessarily “consisting of” or “composed of.” Inother words, the listed steps or options or components need not beexhaustive.

“Liquid” as used herein means that a continuous phase or predominantpart of the composition is liquid and that a composition is flowable at20° C. Solids (e.g., suspended or other) may be included. Gels andpastes are included within the liquids as used herein.

“Reducer” as used herein means a device or a fitting with a constrictedcross-area at the end of the axial flow direction. Flow fluid passingthrough the tube speeds up as it enters the tube's constricted section,results in the generation of high shear and a vacuum, which causes thedosing of a laundry care composition from a laundry care container tothe washing machine. It is highly desirable to have a gradual reductionof diameter to reduce the pressure loss.

“Venturi tube” as used herein means a pipe with a constricted innercross-area (throat); fluid passing through the tube speeds up as itenters the tube's throat, and the pressure drops generating a vacuum,which causes the dosing of a laundry care composition from a laundrycare container to the washing machine. In some sense, a Venturi tube isa combination of a reducer and an enlargement, which has the samestructure as a reducer but also includes the flow from constrictedregion to non-constricted region.

“Along water supply feed” means that the device is connected to thewashing machine via incoming and outgoing water supply hoses, into andout of the device, the outgoing water supply hoses then leading to thewashing machine.

Highly Concentrated Liquid Detegent (HCLD) Compositions

Composition suitable for use in the present inventions comprise from 50%to 100% surfactant, preferably from 60 to 100% of a surfactant,preferably above 65%, and most preferably higher than 75%. Suitablesurfactants are selected from the group consisting of anionic, nonionic,cationic, zwitterionic surfactants and mixtures thereof.

The solvent level is less than or equal to 10%, preferably less than 6%,and most preferably less than 4%. The solvents are selected fromethanol, propanol, propyleneglycol, polypropyleneglycol, glycerin, andother water-soluble organic solvents. Other components in the HCLD mayinclude enzyme, fluorescent dye, builder, buffering agent,anti-redeposition agent, soil release polymer, dye, fragrance, bleachsystem and other minor ingredients.

The water level is less than or equal to 30%, preferably less than 20%,and most preferably less than 10%. The viscosity of HCLD at 21 1/secshear rate is less than 5,000 mPas preferably less than 3,000 mPas andmost preferably less than 1,000 mPas.

The wash dosage is less than 150 g, preferably less than 100 g, morepreferably less than 50 g, and most preferably less than 25 g.

The method of dispensing the HCLD is introducing the HCLD into a highvelocity water stream. The axial velocity at the junction of HCLD andwater flow is greater than 0.25 m/sec, preferably greater than 0.5m/sec, and most preferably greater than 1 m/sec. In general, thevelocity should be less than 10 m/sec to reduce the need forunnecessarily high water pressure.

In general, the required water pressure to produce such velocity isgreater than 3.4 N/cm², preferably greater than 10.2 N/cm², mostpreferably greater than 23.8 N/cm². The HCLD may be introduced to thehigh velocity of water simply by gravitational force, or via a selectionfrom a pump, a pressurized HCLD reservoir or a reducer which generatesvacuum force by speeding up the water speed at the smaller diametersection of the reducer. The pressure of HCLD flow has to be greater thanthe water pressure at the junction.

The flow rate ratio of the HCLD to the water flow is in the range offrom 0.0001 to 0.5, preferably from 0.001 to 0.2, most preferably from0.005 to 0.1, in order to ensure the dispersion and dissolution of HCLD.

For a low water pressure area, a pump may be needed to provide therequired water pressure. The device with pump is highly preferred forwashing machines, which are placed at a low water pressure locations.Otherwise, according to the present invention, the reducer mechanism ispreferred (as demonstrated in FIG. 1), since it has no moving parts, asin the pump. In addition, the reducer-based device does not require apower supply.

Turning now to FIG. 1, a junction of HCLD flow and water flow is at theconstricted section of a reducer. The reducer is installed along thewater supply feed, i.e. a water supply hose. As the water passes throughthe constricted region of the reducer, where the water flow velocityincreases and the HCLD is gradually drawn into the water flow path dueto the vacuum. Not to be bound by the theory, the inventors believe theresults can be contributed by two factors. One, the fast flow of waterdisperses surfactant molecules before its fully hydration and alignmentto each other that the surfactant molecules become structured and formgel in water. Second, the fast water flow has enough kinetic force todestroy any structure that may be formed by the surfactant molecules.

The number of the reducers within the device is generally the same asthe number of water supply hoses. With a single water supply hose, theinventive device with a single reducer is employed, as shown in FIG. 1.

The diameters of the entrance region, De, and the constricted region,Dc, of the reducer play an important factor in the efficiency of themethod. The reduction of the diameter at the constricted region of areducer converts the water pressure, a potential energy, to the kineticenergy and speeding up the water flow velocity. As the De/Dc ratioincreases, the velocity of the water in the constricted regionincreases, thus kinetic energy increases, which better helps to destroyany structure formed by the surfactant molecules in washing liquor.According to the preferred embodiment of the invention, the ratio ofDe/Dc is greater than 1.65, most preferably greater than 2.5, in orderto attain the required vacuum for dosing the products. If the internaldiameter of water hoses is less than the entrance diameter of the end ofthe reducer (De), then the preferred ratio should be based on the ratioof the internal diameter of water hose to the diameter of the throat ofthe reducer (Dc).

The inventive system may be further connected to another system of areducer and a laundry booster composition, which is an aqueous productcontaining ingredients selected from surfactant, enzyme, fluorescentdye, builder, buffering agent, anti-redeposition agent, soil releasepolymer, dye, fragrance, and bleach system or mixtures thereof. It ispreferred to dose the booster and HCLD sequentially. Buffer and builderare preferably dosed prior to the dosing of HCLD and the bleach systemis preferably dosed after the dosing of HCLD. The reducer/compositionsystems may be daisy chained together.

Intermediate Dosing Chamber

In another embodiment of the present invention, an intermediate chamberis added along the passage connecting the laundry care dosing containerand the reducer or the pump to provide a better control for a user. Acheck valve is located between the chamber and the reducer or the pump.The other end of the chamber is connected to a product container with abuilt-in on/off valve, which is used to control the flow of product fromthe laundry care product container to the intermediate chamber. Ano-ring, as a seal, is located the intake stem above the on-off valve.The see-through chamber has various dosage lines for different dosage.

The intermediate dosing chamber is pre-filled by opening the on-offvalve between the product container and the intermediate chamber. Theon/off valve is manually controlled. Alternatively, the manual on-offvalve can be also replaced with a solenoid valve, which is controlled bythe algorithm to open the solenoid valve at various times for variousdosages according to the combination of the selection of load size andthe degree of dirt in the wash load.

EXAMPLE 1 AND COMPARATIVE EXAMPLE A

The composition of Example 1 (within the scope of present invention) wasprepared by first forming two premixes. Typically, premix I was preparedby first mixing LAS and Neodol® 25-7 to form a clear solution, and lateradding NaOH to reached complete neutralisation. Finally, TEA was addedto Premix I as a buffering agent. Premix II was prepared by mixingflorescent dye with water and Neodol® 25-7 until complete dissolutionwas reached. The two premixes were then mixed together, forming the mainmix, where sodium LES, ethanol, propyleneglycol and enzyme were finallyadded and blended in to reach homogenous mixture, which was a flowableliquid at room temperature. The composition for Example 1 is summarisedin Table 1. TABLE 1 wt % Premix I Neodol ® 25-7 25.75 LAS acid 26.46NaOH 6.79 Triethanolamine 1.29 Premix II water 1.29 Whiting agent 0.32Neodol ® 25-7 12.87 Sodium LES 18.41 ethanol 1.29 Propylene glycol 3.99Misc. To 100 Total surfactant, % 78.95 Q_(d)/Q_(p)* 0.001 Velocity**,m/sec 1.5*Q_(d)/Q_(p) is the flow rate ratio of the detergent composition to theflow rate.**Axial velocity at the constricted region of the reducer.

The device, which is a reducer with De/Dc ratio of 2, was connected to atap water faucet. When the water was turned on, 3 gram of HCLD of thecomposition detailed in Table 1 was sucked, dispersed and dissolved intothe washing liquor without forming any gel phase. Totally 3 liters ofwater and 3 grams of Example 1 were collected in the bucket. Thedissolution of the surfactant molecules was immediate and no gelformation was observed.

Comparative Example A was carried out by adding 3 grams of the Example 1to 3000 gram of water (room temperature), in the absence of the reducerdevice, and so in the absence of the requisite pressure and flow rateparameters. Because the water was still, the water velocity was 0 m/secfor Comparative example A. Gel immediately formed as the compositioncame into contact with the water.

1. A laundry detergent system comprising: (a) a highly concentratedliquid laundry detergent composition comprising: (a1) a surfactant,selected from anionic, nonionic, cationic surfactants and mixturesthereof in an amount of from about 50% to about 100%, by weight of thecomposition; and (a2) a solvent in an amount of from about 0% to about10%; and (b) a device connected to a water supply feed, that providesthe injection pressure of the detergent composition being greater thanwater flow pressure at the junction of the detergent composition and thewater flow and water flow rate at the junction of greater than 0.25m/sec; (c) wherein the flow rate ratio of the detergent composition tothe water flow is in the range of from about 0.0001 to about 0.5.
 2. Thesystem of claim 1 wherein the device comprises a reducer installed alongthe water supply feed.
 3. The device of claim 2 wherein the ratio of theinternal diameters of the entrance and exit the reducer is greater than1.65.
 4. The device of claim 2 wherein the ratio of the internaldiameter of a water supply feed hose to the internal exit diameter ofthe reducer is greater than 1.65.
 5. The device of claim 2 wherein thereducer is a Venturi tube.
 6. The system of claim 1 wherein the devicecomprises a pump.
 7. The system of claim 1 wherein the water content ofthe composition is less than 30%.
 8. The system of claim 1 wherein thecomposition contains functional ingredients selected from a groupcomprises of enzyme, fluorescent dye, builder, buffering agent,anti-redeposition agent, soil release polymer, dye, fragrance, andbleach system.
 9. The system of claim 1 wherein the device comprises anintermediate dosing chamber.
 10. The system of claim 1 wherein thesystem is connected to another system comprising a reducer and a laundrybooster composition.
 11. The system of claim 10 wherein the laundrybooster composition is an aqueous product containing ingredientsselected from the group consisting of surfactant, enzyme, fluorescentdye, builder, buffering agent, anti-redeposition agent, soil releasepolymer, dye, fragrance, bleach system and mixtures thereof.
 12. Thesystem of claim 11 wherein the booster and the concentrated liquiddetergent dose sequentially.